This project covers a broad range of studies which focus on elucidating risk factors for, and the natural history of, esophageal adenocarcinoma (esophageal cancer) and the precursor lesion Barretts esophagus (aka Barrett esophagus). Barretts esophagus is a metaplastic change in the lower esophagus which is characterized by the replacement of the native squamous cell epithelium with a glandular-type of epithelium. This metaplastic change is thought to be primarily the result of genotoxic damage induced by gastroesophageal refluxacid and bile salts reflux up into the esophagus, exposing cells not equipped to deal with these reactive chemicals. Re-epithelization with the metaplastic Barretts epithelium provides for a tissue which is better able to withstand the exposure to such compounds. However, it also increases the risk of esophageal adenocarcinoma approximately 10-50 fold that of the general population. The incidence of esophageal adenocarcinoma has increased over 650% in the United States over the last 35 years and most individuals present with late stage malignancies, resulting in a 5-year survival rate of less than 20%. This indicates that researchers need to be able to better identify those at high risk and Barretts esophagus is a good starting point. However, although this metaplasia greatly increases the risk of esophageal adenocarcinoma relative to the general population, the absolute risk remains low at around 0.5% or 1 in 200 patient years of follow-up. This is because approximately 90% of individuals who develop esophageal adenocarcinoma are diagnosed at their first (index) endoscopy. Thus, not only do we need to be able to better identify those with high risk (Barretts esophagus) in the general population, we also need to be able to triage these individuals into high and low risk groups so that surveillance resources can be focused on those who most need them, which would make the cost-benefit equation of surveillance endoscopy more attractive. Therefore, the ultimate goals of all the studies within this project seek to better understand the natural history of this disease, risk factors for progression, diagnostic markers and modalities with high sensitivity, and prognostic biomarkers for efficient triaging of risk.The Barrett's Esophagus Consortium project (CAS ID:10593) is a pooling project that brings together and harmonizes data from eight case-control studies of Barrett's esophagus and fourteen case-control studies of esophageal adenocarcinoma. The consortium has published many articles, details of which can be seen at http://beacon.tlvnet.net/ The Esophageal Cancer in SEER-Medicare project (CAS ID:10633) is assessing metabolic syndrome in relation to Barrett's esophagus (published in Journal of Clinical Gastroenterology) and esophageal adenocarcinoma (manuscript submitted) as well as the comparative utility of staging modalities in relation to survival following diagnosis of esophageal adenocarcinoma (published in Cancer). We are also assessing whether there is are demographic, medical history, and survival differences in esophageal adenocarcinoma by whether there was a prior diagnosis of the precursor condition Barrett's esophagus (submitted for publication). A new project will assess whether we can develop an algorithm to accurately identify diagnoses of esophageal adenocarcinoma using Medicare billing data alone.The CPRD EAC Progression Study has assessed whether metabolic syndrome is a risk factor for progression from Barretts esophagus to esophageal adenocarcinoma. This analysis is based in the Clinical Practice Research Datalink (CPRD) which was formerly called the General Practice Research Database (GPRD). The manuscript has been published in Cancer Epidemiology. In the Hormones in Barrett's Esophagus project (CAS ID:10638) we have assessed circulating androgens and estrogens in Barrett's esophagus patients compared with gastroeosphageal reflux disease controls in the BEEDS study based atthe Walter Reed (published in Clinical Gastroenterology and Hepatology). We are currently assessing similar exposures in a second Barrett's esophagus population for external replication (manuscript being drafted) as well as expansion to esophageal cancer (adenocarcinoma) using three cohort studies.The Kaiser BE Cohort project has enabled us to assess cancer and mortality risks amongst a large Barretts esophagus cohort. These analyses will provide evidence that is directly applicable for a Barretts esophagus population undergoing surveillance. The manuscript has been submitted for publication.The inflammation markers and esophageal adenocarcinoma (CAS 10731) is beinging together esophageal adenocarcinoma cases and controls from seven cohorts. We are assessing a suite of circulating inflammation markers and testing whether these are associated with risk of developing esophageal adenocarcinoma. Laboratory analyses are currently being conducted. All of these projects are closely aligned to the aims of elucidating the etiology of Barrett's esophagus and esophageal adenocarcinoma as well as providing potential utility for diagnostics and prognostics.